Climate control systems of the above-described kind exist in many installations and represent a considerable consumption of energy. For users in general and for the global society in particular, less consumption of energy is desirable. While new systems can offer energy savings at a maintained level of climate comfort, only a minor part of installations presently used are likely to be replaced in a near future. Instead of accepting the cost of a new installation, users may choose less comfort so as to reduce the energy consumption. If an adapter would save energy without loss of climate comfort, it could find a huge market.